Table 1 Parameters used for simultaneous rate equations model
From: Chip-scale high-peak-power semiconductor/solid-state vertically integrated laser
Symbol | Parameter | Value |
|---|---|---|
ηi | Carrier injection efficiency | 0.99 |
Ioff | Offset current | 0.49 A |
G0 | Initial gain coefficient | 2.6 × 105 s−1 |
N0 | Carrier transparency number | 1.8 × 105 |
β | Spontaneous emission coefficient | 6.9 × 10−17 |
ε | Gain compression coefficient | 9.9 × 10−28 |
k | Scale-factor of the output coupling efficiency | 1.0 × 10−7 W |
τn | Carrier lifetime in the VECSEL cavity | 9.9 × 10−9 s |
τp | Photon lifetime in the VECSEL cavity | 9.8 × 10−12 s |
I | Injected current | 0.91 A |
lsub | Length of the GaAs substrate | 0.1 mm |
tV = 2(nsublsub + nYAGlg)/c | VECSEL external cavity round-trip time | 8.4 × 10−12 s |
AYb | Single-pass absorption rate of Yb:YAG | 18.1% |
σg | Stimulated emission cross section of Yb:YAG | 2.2 × 10−20 cm2 |
σSA | Ground-state absorption cross section of Cr:YAG | 4.6 × 10−18 cm2 |
σESA | Excited-state absorption cross section of Cr:YAG | 8.2 × 10−19 cm2 |
lg | Length of Yb:YAG | 0.5 mm |
lSA | Length of Cr:YAG | 0.2 mm |
NSAi = −ln(T02)/(2σSAlSA) | Total population density of Cr:YAG | 5.6 × 1017 cm−3 |
tr = 2nYAG (lg+lSA)/c | Q-switched laser cavity round-trip time | 8.5 × 10−12 s |
τg | Lifetime of the upper laser level of Yb:YAG | 9.5 × 10−4 s |
τSA | Excited-state lifetime of Cr:YAG | 3.4 × 10−6 s |
γg | Inversion reduction factor of Yb:YAG | 2 |
Ni | Total population density of Yb:YAG | 5.5 × 1020 cm−3 |
hc/λp | Photon energy | 2.1 × 10−19 J |
λp | Pumping wavelength | 940 nm |
F | Intensity adjustment factor | 2.9 |
D | Diameter of pumping laser | 0.16 mm |
V = π(D/2)2 × lg | Pumping volume | 1.0 × 10−2 mm3 |
L | Nonsaturable round-trip dissipative optical loss | 0.05 |
c | Vacuum speed of light | 3.0 × 108 m/s |
q | Elementary charge | 1.6 × 10−19 C |
nsub | Refractive index of the GaAs substrate | 3.55 |
nYAG | Refractive index of the laser crystal | 1.82 |
ROC | Reflectance of the OC | 85% |
T0 | Initial transmittance of Cr:YAG | 95% |
